Ontogenetic changes in habitat use by whitefish, Coregonus lavaretus

Abstract

SynopsisThe whitefish, Coregonus lavaretus, in the lake Mjosa exhibited two niche changes during their life cycle. Juveniles (< 2.5 cm body length) were confined to the shallow (0-30m) epibenthic zone. Medium sized whitefish (25-35 cm body length) expanded their habitat use to include the deep (30-90 m) epibenthic zone as well as the pelagic zone. From a body length of 35 cm, habitat use was restricted to the deep epibenthic zone. Small fish in the shallow epibenthic zone ate small and medium-sized prey (zooplankton, insect larvae and surface insects). Medium-sized fish in this zone were in addition feeding on the larger amphipod, Pallasea quadrispinosa. In the pelagic zone, the diet of medium-sized whitefish was dominated by zooplankton, although some larger prey like surface insects and age-0 smelt, Osmerus eperlanus, were also eaten. In the deep epibenthic zone, the diet of both medium-sized and large (< 35 cm) whitefish consisted mainly of the large prey P. quadrispinosa.

Partial migration: niche shift versus sexual maturation in fishes

“…In the Norwegian Lake Mjosa, whitefish grow up in littoral waters. However, at body lengths of about 25 era, some of the littaoral fish move from epibenthic to pelagic areas to feed on small crustacean zooplankton during summer in Lake Mjosa (N~esje et al, 1991;Sandlund et aL, 1992). Whitefish larger than 35 era, however, do not undertake this phenological habitat shift.…”

Niche use and resource partitioning of Arctic charr, European whitefish and grayling in a subarctic lake

“…Also grayling are known occasionally to feed in the pelagic zone (Merric et al, 1992;Haugen & Rygg, 1996), but usually they are found in the littoral zone feeding on zoobenthos (Northcote, 1995;Haugen & Rygg, 1996). Grayling rarely occur in the profundal (Haugen & Rygg, 1996), whereas Arctic charr and whitefish may also frequently utilize this zone as feeding habitat (Langeland et al, 1991;Sandlund et al, 1992;Klemetsen et al, 1997;Kahilainen et al, 2004;Knudsen et al, 2006).…”

Sexual Size Dimorphism and Ecomorphology of Spotfin Shiner (Cyprinella spiloptera) from the Wabash River Watershed

“…Variation in morphology can involve ecological differences among species (Gans and Gaunt 1977, Wiilemiller 1991, Garland and Losos 1994, Schaefer et al 1999, Irschick 2002: Billman and Pyron 2005 or within species (Van Valen 1965, McGuigan et al 2003, Langerhans et al 2004. Morphological variation that has been identified within species can be a function of predation regime (Langerhans et al 2004), local competition (Gatz 1979, Strauss 1987, foraging tactic (Toline and Baker 1993), latitude (Milano et al 2006), or habitat (Sandlund et al 1992). For example, morphological variation among individual brown trout produced variation in swimming speed and endurance (Ojanguren and Brana 2003).…”